The invention relates to a lubricating oil supplying arrangement for an apparatus having a rotating apparatus shaft and an oil pump, which is arranged at one end of the apparatus shaft and the displacement elements of which are driven by the apparatus shaft.
Such an arrangement is known from EP 0 811 767 A1. In a radial bearing housing for a compressor shaft, on the end face remote from the shaft there is provided a circular recess for receiving the internally toothed annular gear of a gerotor gear assembly. The apparatus shaft arranged eccentrically with respect thereto drives with its end portion the associated externally toothed gearwheel of the gerotor gear assembly. The whole assembly is closed off on the free side by a cover. Achieving the correct fit between moving and non-moving parts presents difficulties here. In addition, assembly is complicated.
The invention is based on the problem of simplifying the construction of an oil pump for an apparatus of the kind described in the introduction.
That problem is solved in accordance with the invention in that the pump housing comprises a pocket in the form of a chamber open on one side, in which the displacement elements are so arranged that the pump housing covers the displacement elements axially on both sides at least in an operative region and in the circumferential direction over a maximum of 180xc2x0, the displacement elements are held in position by a pump shaft, which passes through one displacement element and is connected thereto so that they rotate together, and the pump shaft is connected by way of coupling elements to the apparatus shaft so that they rotate together.
In this construction, the oil pump is pre-fabricated such that the displacement elements are inserted radially into the pocket of the pump housing and are held in position there by insertion of the pump shaft. In this case, very narrow tolerances can be achieved. Assembly too is simple. Afterwards, all that is required is to connect the pump housing to a stationary part of the apparatus and to couple the apparatus shaft to the pump shaft.
It will be noted that the non-prior-published DE 197 17 295.4 describes a fluid machine, in which the housing has a pocket in the form of a chamber open on one side, in which the displacement elements are so arranged that the housing covers the displacement elements axially on both sides at least in an operative region and in the circumferential direction over a maximum of 180xc2x0. Furthermore, the displacement elements are held in position by a shaft that passes through one displacement element and is connected thereto so that they rotate together. Express reference will be made to numerous further details that can be derived from the prior application and which are also useful for development in the present case.
In a preferred construction, provision is made for the pump housing to cover an end-face recess of the apparatus shaft and for the coupling elements to be arranged in this recess. Housing the coupling elements in the recess of the apparatus shaft enables the apparatus shaft to be given a considerably larger diameter than the pump shaft, as is desirable for mechanical reasons.
It is advisable for the coupling elements to comprise a transverse bolt passing radially through the recess, the bolt having an annular channel at its middle, and, on the pump shaft, a fork engaging in the annular channel. This permits simple assembly.
It is especially advantageous if the pump housing is inserted in a radial bearing housing receiving one end of the apparatus shaft and is secured there against rotation and forms an axial bearing for the apparatus shaft. During assembly, it is sufficient for the end of the apparatus shaft to be simply inserted in the radial bearing housing and be rotated until the coup ling elements engage one another. Moreover, the pump housing assumes an additional function.
In this connection, it is advantageous for the pump housing to be arranged at the lower end of a vertically positioned apparatus shaft. The a pparatus shaft then lies by virtue of its own weight against the axial bearing.
It is also advisable for the pocket to be located in the lower part of the pump housing. In t he case of this configuration, the open part of the pocket is located in the oil sump, so that no further additional measures have to be taken for oil intake. A rapid oil supply is therefore ensured as soon as the pump shaft starts a rotation. Delays because of intake are significantly reduced.
It is especially advantageous for at least one lubricating duct to lead out from the recess and for pressure ducts to be provided in the pump housing in the operative region, which open out into the end-face recess of the apparatus shaft. The pressure ducts can be formed by simple axially parallel bores. The recess serves as a collecting space for the lubricating oil under pressure.
A lubricating duct preferably runs in the apparatus shaft, as is already known for refrigerant compressors.
Alternatively or at the same time, a lubricating duct can also lead to the radial bearing of the apparatus shaft.
In the latter case, it is advisable for the transverse bolt to have two longitudinal bores, which each connect a respective transverse bore with an annular channel provided in the radial bearing housing and adjacent to the radial bearing. This produces a low-resistance lubricating duct.
In addition, it is advantageous for the displacement elements to be gerotor gear assemblies. This produces an especially good oil-conveying action.
It is also advantageous for the apparatus to be a spiral compressors. Such compressors are known, for example, from DE 33 00 838 A1. With the motor running they convey a relatively large amount of refrigerant constantly.
The oil pump can also be used to advantage when the apparatus is a different compressor, especially a piston compressor, a motor, especially a combustion motor, or a pump.